Methods and systems for manufacturing woven retention devices

ABSTRACT

A method and system for manufacturing a woven retention device including: providing a loading pattern of a first plurality of filaments on a first set of tensioned carriers and a second plurality of filaments on a second set of tensioned carriers; rotating the first set of tensioned carriers in a first direction and rotating the second set of tensioned carriers in a second direction; interweaving the first and second plurality of filaments at a predetermined braid angle of intersection to form the woven retention device, wherein the interweaving creates pairs of the first plurality of filaments and pairs of the second plurality of filaments. The woven retention device can be manufactured such to include a plurality of aperture sizes, and such that each of the filaments of the first plurality of filaments and the filaments of the second plurality of filaments have an offset weaving configuration

TECHNICAL FIELD

The present invention relates to systems and methods for manufacturing woven retention devices.

BACKGROUND

In orthopedic surgery it is common to secure a bone screw to a patient's bone. Bone fracture repair is surgery to fix a broken bone using plates, nails, screws, or pins. It is common in the treatment of fractures to attach a plate to the bone utilizing bone screws. The resulting construct prevents motion of the fractured bone so that the bone can heal. Alternatively, one or more screws may be inserted across the break to hold it place.

In the treatment of spinal disorders, pedicle screws are inserted into the patient's vertebrae to serve as anchor points that can then be connected with a rod. This construct prevents motion of the vertebral segments that are to be fused.

In the treatment of detached tendons, screw-like tissue anchors are inserted into the patient's bone to serve as an anchor for the reattachment of the tendon.

One complication with the use of bone screws is the loss of fixation or grip between the bone screw and the patient's bone. Another complication with the use of bone screws is the stripping of the hole in the bone when the bone screw is inserted. This results in the loss of purchase and holding strength of the bone screw.

The presence of osteoporotic bone can increase the likelihood of complications by reducing the purchase or grip of the bone screw to the patient's bone, resulting in a loss of holding strength and loosening of the bone screw or pullout of the bone screw.

Current solutions to secure bone screws have not adequately addressed screw failure and the underlying causes of screw failure. What is needed are methods and systems for manufacturing woven retention devices for securing bone screws.

SUMMARY

In an aspect of the invention, a method of manufacturing a woven retention device can include providing a loading pattern of a first plurality of filaments on a first set of tensioned carriers and a second plurality of filaments on a second set of tensioned carriers; rotating the first set of tensioned carriers in a first direction and rotating the second set of tensioned carriers in a second direction; and interweaving the first and second plurality of filaments at a predetermined braid angle of intersection to form the woven retention device, the woven retention device having an inner diameter. The interweaving can create pairs of the first plurality of filaments and pairs of the second plurality of filaments, wherein spacing in between the pairs results in a plurality of aperture sizes through the woven retention device. Each of the filaments of the first plurality of filaments and the filaments of the second plurality of filaments can have an offset weaving configuration.

The filaments of each of the pairs of the first plurality of filaments can have an offset two-over/two-under weaving configuration and the filaments of each of the pairs of the second plurality of filaments can have an offset two-over/two-under configuration.

The method can further include rotating a plurality of rotors including the first and second tensioned carriers. A first set of the plurality of the rotors can rotate in the first direction and a second set of the plurality of rotors can rotate in the second direction.

Each rotor can have at least four inlets that are configured to accept carriers. The at least four inlets can have a predetermined spatial relationship that includes the at least four inlets being unevenly spaced. The rotating can include carriers alternatingly switching either from one of the at least four inlets of one of the first set of the plurality of rotors to one of the at least four inlets of one of the second set of the plurality of rotors or from one of the at least four inlets of one of the second set of the plurality of rotors to one of the at least four inlets of one of the first set of the plurality of rotors. The carriers alternatingly switching in a predetermined spatial configuration can create the interweaving. The carriers alternatingly switching in the inlets can have the predetermined spatial relationship around the rotors creating the offset two-over/two-under configuration.

The at least four inlets can include a first and a second pair of inlets, and for each rotor, the predetermined spatial relationship can include both inlets of each pair being about a same distance from each other.

The filaments can be about 0.2 mm, 0.1 mm, and 0.4 mm in diameter.

The ones of the pairs of the first plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the first plurality of filaments can be about 0.2 mm in diameter. Ones of the pairs of the second plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the second plurality of filaments can be about 0.2 mm in diameter.

Ones of the pairs of the first plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the first plurality of filaments can be about 0.4 mm in diameter. Ones of the pairs of the second plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the second plurality of filaments can be about 0.4 mm in diameter.

Ones of the pairs of the first plurality of filaments can be about 0.2 mm in diameter and others of the pairs of the first plurality of filaments can be about 0.4 mm in diameter. Ones of the pairs of the second plurality of filaments can be about 0.2 mm in diameter and others of the pairs of the second plurality of filaments can be about 0.4 mm in diameter.

Ones of the pairs of the first plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the first plurality of filaments can be about 200 dtex, and ones of the pairs of the second plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the first plurality of filaments are about 200 dtex.

The interweaving of the first and second plurality of filaments can create a balanced state of the woven retention device, and the woven retention device can be configured to resist torsion in clockwise and counterclockwise directions.

The balanced state can result from diameters of the first plurality of filaments equaling diameters of the second plurality of filaments.

The first set of tensioned carriers can include 24 carriers and the second set of tensioned carriers can include 24 carriers.

The first plurality of filaments can include flat multifilaments and the second plurality of filaments can include round monofilaments.

The interweaving can form a textile strength of the woven retention device that is changed based on pique count, filament thickness, braid angle, and bobbin count.

The braid angle of the filaments can be between about 40 and 45 degrees.

The loading pattern can be configured with a carrier map, which can associate each carrier with its filament.

The method can further include providing a mandrel wherein the interweaving uses the mandrel to create the hollow structure shape. The mandrel can be heated to shape the interwoven filaments.

The method can further include collapsing the hollow structure into a flattened tube and winding the flattened tube around a spool; and unwinding the spool and cutting the spool into individual segments. The method can further include tapering a distal portion of the woven retention device.

The method can further include tapering a distal portion of the woven retention device.

The inner diameter can be about 6.5 mm.

The interweaving can include interweaving the first and second sets of filaments to create a biaxial braid pattern.

The method can further include providing a plurality of longitudinal filaments. The interweaving can include interweaving the first and second sets of filaments with a set of longitudinal filaments, the interweaving creating a triaxial braid.

In another aspect of the invention, a system of manufacturing a woven retention device, can include a first plurality of filaments on a first set of tensioned carriers and a second plurality of filaments on a second set of tensioned carriers. The first set of tensioned carriers cam be configured to rotate in a first direction and the second set of tensioned carriers can be configured to rotate in a second direction. The system can include a mandrel that is configured to interweave the first and second plurality of filaments at a predetermined braid angle of intersection to form the woven retention device. The woven retention device can have an inner diameter. The interweaving can create pairs of the first plurality of filaments and pairs of the second plurality of filaments. Spacing in between the pairs can result in a plurality of aperture sizes through the woven retention device. Each of the filaments of the first plurality of filaments and the filaments of the second plurality of filaments can have an offset weaving configuration.

Additional features, advantages, and embodiments of the invention are set forth or apparent from consideration of the following detailed description, drawings and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a perspective view of a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 1B shows a top view of a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 1C shows a top view of movements of carriers of a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 2 shows a rotor of a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 3 shows a top view of a braiding system for manufacturing a woven retention device with carriers, in accordance with one embodiment of the invention.

FIG. 4A shows movement patterns for four different carriers in a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 4B shows movement patterns for two different carriers in a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 4C shows movement patterns for four different carriers in a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 4D shows movement patterns for four different carriers in a braiding system for manufacturing a woven retention device, in accordance with one embodiment of the invention.

FIG. 5 shows a portion of a manufactured woven retention device, in accordance with one embodiment of the invention.

FIG. 6A shows intersecting filaments of a woven retention device in a balanced state, in accordance with one embodiment of the invention.

FIG. 6B shows intersecting filaments of a woven retention device in an unbalanced state, in accordance with one embodiment of the invention.

FIG. 7 shows intersecting filaments of a woven retention device in a one-over/one-under configuration, in accordance with one embodiment of the invention.

FIG. 8 shows intersecting filaments of a woven retention device in a two-over/two-under configuration, in accordance with one embodiment of the invention.

FIG. 9 shows intersecting filaments of a woven retention device in a three-over/three-under configuration, in accordance with one embodiment of the invention.

FIG. 10 shows triaxial braiding of a woven retention device, in accordance with one embodiment of the invention.

Additional features, advantages, and embodiments of the invention are set forth or apparent from consideration of the following detailed description, drawings and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.

DETAILED DESCRIPTION

The systems and methods described herein may be directed to manufacturing devices used in the area of orthopedics and, in particular, orthopedic repairs. These systems and methods can include manufacturing various devices, systems and methods directed to fixing and/or retaining fasteners in orthopedic applications. Fixing or retaining fasteners to bone tissue is complicated by the underlining bone tissue. Understanding that an underlying cause of failure with internal fixation in bone tissue is the bone, the systems and methods for manufacturing devices, systems and methods described herein provide for solutions that address the implant site. At the implant site, the hole and the bone benefit from an enhanced interface.

The systems and methods for manufacturing fixation and/or retention devices, systems and methods described herein maximize fixation and/or retention in the bone tissue, including, osteoporotic bone, bone of a poor quality, and mechanically poor bone in addition to healthy bone tissue. The fixation and/or retention devices, systems and methods described herein may be used with any type of fixation including, any types of screws.

FIG. 1A shows a system 100, which can be used in a method of manufacturing a woven retention device 110. As shown in FIG. 1A, the method can include providing a loading pattern of a first plurality of filaments 108 on a first set of tensioned carriers 104 and a second plurality of filaments 106 on a second set of tensioned carriers 102.

As can be seen from arrows 112, 114, the method of manufacturing can include rotating the first set of tensioned carriers 104 in a first direction 112 and rotating the second set of tensioned carriers 102 in a second direction 114. The method can also include interweaving the first and second plurality of filaments 106, 108 at a predetermined braid angle of intersection to form the woven retention device 110.

In one embodiment, the interweaving creates pairs of the first plurality of filaments 108 and pairs of the second plurality of filaments 106, wherein spacing in between the pairs results in a plurality of aperture sizes through the woven retention device 110. In one embodiment, each of the filaments of the first plurality of filaments 108 and the filaments of the second plurality of filaments 106 have an offset weaving configuration. As shown in FIGS. 1A and 1B, the method can include providing a mandrel 160 that is used in the interweaving to create the hollow structure shape of the woven retention device. The woven retention device 110 can have an inner diameter 120. In one embodiment, the inner diameter can be about 6.5 mm.

FIG. 1B shows a top view of a method of manufacturing a woven retention device 110. In one embodiment, the interweaving can be performed using spools of material, carriers or bobbins, which can be mounted into a framework pattern. The bobbins can either go in a first direction 112 or a second direction 114 as they weave or interlace, which can yield the interweaving or interlacing pattern. In this embodiment, two sets of helical strands can interlace with each other, member strands of the same set can travel in concurrent paths and intersections can occur with strands of the opposite set. The interweaving can be used for creating a plurality of different protuberance thicknesses in the woven retention device 110.

Various characteristics in the method for manufacturing the woven retention devices can affect the contours of the woven retention device 110. For example, some of the characteristics can include the size of the filaments, the braid angle of the interweaved filaments, as well as other metrics that can give a greater or lesser surface roughness or surface discontinuity. The other metrics can include controlling the characteristics of the filaments and the interweaving arrangement for example, by using filaments of small thickness, their related interference or height differential, or pique count, the resulting protuberances can be relatively small. On the other hand, if a filament having a small thickness is interweaved with a filament having a large thickness, the disruption or the change in height is small relative to the filament having a large thickness. However, interweaving a filament having a large thickness with a filament having a large thickness can result in more profound surface roughness, both internal and external. Thus, surface discontinuity can be used to interdigitate with surrounding structure, whether with the bone or with an orthopedic screw. Filament thickness can also affect durability or rigidity of the woven retention device 110. For example, a large diameter mono filament can have an inherently stiffer, more rigid characteristic than a small diameter mono filament or for that matter the flat multi filament strands. Thus, filament thickness can affect ultimate rigidity of the resulting structure, the ability to return to its natural state the ability to have various characteristics and torsion resistance.

In one embodiment, the woven retention device 110 can be made in a way that provides for a flexible diameter, good conformability and drape. In one embodiment, fibers can be provided in the bias direction only. The orientation of the construction dependent fiber can range from 15-75 degrees. As seen in FIG. 7, the braid can be constructed in a diamond or plain braid in a 1/1 (one-under/one-over) manner, which allows for a tighter wave that has less radial support, column strength and torque transmission. As seen in FIG. 8, the braid can be constructed in a regular braid or twill in a 2/2 (two-under/two-over) manner, which allows for more radial support, column strength and torque transmission. As seen in FIG. 9, the braid can also be constructed in a Hercules braid in a 3/3 (three-under/three-over) manner, which allows for even more radial support, column strength, and torque transmission.

Further, the one-over/one-under or the two-over/two-under or three-over/three-under differences can affect the protuberances and surface roughness of the woven retention device. For example, a one-over/one-under can have a more pronounced surface roughness than a three-over/three under because of the shorter distance that an interweaving filament must travel to cover the interweaving distance.

FIG. 1C shows the movement of various carriers around a center of the system 100 for manufacturing. In one embodiment, as seen in FIG. 1C, the center of the system can be a mandrel 160.

FIG. 2 shows one rotor (or horn gear) that is configured to receive a plurality of carriers. Each rotor can rotate either in a first direction 119 or in a second direction 118, as shown in FIG. 1B.

As can be seen in FIG. 2, an inlet 204 can receive one of either a first plurality of carriers 204 or a second plurality of carriers 206. The filaments of each of the pairs of the first plurality of filaments 108 can have an offset two-over/two-under weaving configuration and the filaments of each of the pairs of the second plurality of filaments 106 have an offset two-over/two-under configuration.

In one embodiment, and as seen in FIG. 3, the method includes rotating a plurality of rotors including the first and second tensioned carriers, wherein a first set of the plurality of the rotors 340 rotate in the first direction 318 and a second set of the plurality of rotors 342 rotate in the second direction 319. In one embodiment, the first and second sets of plurality of rotors are alternately disposed between each other. In one embodiment, the method of manufacturing can align the filaments such that the predetermined braid angle of the filaments is between about 40 and 45 degrees.

As seen in FIG. 3, each rotor can have at least four inlets 202 that are configured to accept carriers (e.g., carriers 302, 304), and the at least four inlets 202 can have a predetermined spatial relationship that includes the at least four inlets being unevenly spaced around the rotor. For example, the inlets can be bunched close together on one side of the rotor leaving an opposing side without inlets. The rotor can include carriers alternatingly switching either from one of the at least four inlets of one of the first set of the plurality of rotors 340 to one of the at least four inlets of one of the second set of the plurality of rotors 342 or from one of the at least four inlets of one of the second set of the plurality of rotors 342 to one of the at least four inlets of one of the first set of the plurality of rotors 340. FIG. 3 shows carriers 370 in the act of switching from a left rotor rotating in the first direction 318 to a right rotor rotating in the second direction 319. The carriers alternatingly switching in a predetermined spatial configuration can create the interweaving of the woven retention device 110. The carriers alternatingly switching in the inlets having the predetermined spatial relationship around the rotors can create an offset two-over/two-under configuration.

In one embodiment, the at least four inlets can include a first and a second pair 208 of inlets. For each rotor, the predetermined spatial relationship can include each pair of inlets being spaced about a same distance from each other. In the second pair 208 of inlets, carriers 210 and 212 are shown in FIG. 2.

As seen in FIG. 4B, because of the alternately rotating rotors with carriers proceeding in opposing directions, carriers 130, 132 can move in an arrangement of one carrier moving in and out over the other carriers. In one embodiment, each of the first and second plurality of filaments can be about 0.2 mm in diameter. Alternatively, each of the filaments can have other thicknesses in a range of about 0.1 mm to 0.4 mm. For example, each of the first and second plurality of filaments can be about 0.1 mm thick. In another embodiment, each of the first and second plurality of filaments can be about 0.4 mm thick. As shown in the legend of FIG. 4B, the number of the first plurality of filaments can be 24 and the number of the second plurality of filaments can be 24. Thus, in one embodiment the first set of tensioned carriers can include 24 carriers and the second set of tensioned carriers can include 24 carriers. This can translate into the system 100 having two carriers per rotor.

As seen in FIG. 4C, the filaments can be a plurality of filaments having different thicknesses. FIG. 4C shows that some 136 of the pairs of the first plurality of filaments are about 0.1 mm in diameter and others 134 of the pairs of the first plurality of filaments are about 0.2 mm in diameter, and some 140 of the pairs of the second plurality of filaments are about 0.1 mm in diameter and others 138 of the pairs of the second plurality of filaments are about 0.2 mm in diameter. As shown in the legend of FIG. 4C, the system 100 can include twelve of each of the differently thick filaments of the first plurality of filaments and twelve of each of the differently thick filaments of the second plurality of filaments.

Alternatively, as seen in FIG. 4D, the filaments can be a plurality of filaments having different thicknesses. FIG. 4D shows that some 142 of the pairs of the first plurality of filaments are about 0.4 mm in diameter and others 144 of the pairs of the first plurality of filaments are about 0.1 mm in diameter, and some 14 of the pairs of the second plurality of filaments are about 0.2 mm in diameter and others 148 of the pairs of the second plurality of filaments are about 0.1 mm in diameter. As shown in the legend of FIG. 4D, the system 100 can include twelve of each of the differently thick filaments of the first plurality of filaments and twelve of each of the differently thick filaments of the second plurality of filaments.

Alternatively, in another embodiment, ones of the pairs of the first plurality of filaments are about 0.1 mm in diameter and others of the pairs of the first plurality of filaments can be about 0.4 mm in diameter, and ones of the pairs of the second plurality of filaments can be about 0.1 mm in diameter and others of the pairs of the second plurality of filaments can be about 0.4 mm in diameter.

Alternatively, ones of the pairs of the first plurality of filaments can be about 0.2 mm in diameter and others of the pairs of the first plurality of filaments can be about 0.4 mm in diameter, and ones of the pairs of the second plurality of filaments can be about 0.2 mm in diameter and others of the pairs of the second plurality of filaments can be about 0.4 mm in diameter.

In one embodiment, the first and second plurality of filaments can include multifilaments in combination with monofilaments. In one embodiment, the first plurality of filaments can include flat multifilaments and the second plurality of filaments can include round monofilaments. In FIG. 4A, some 120 of the pairs of the first plurality of filaments can be monofilaments having a thickness of about 0.2 mm in diameter and others 122 of the pairs of the first plurality of filaments can be multifilaments of about 200 dtex, and some 124 of the pairs of the second plurality of filaments can be monofilaments having a thickness of about 0.2 mm in diameter and others 126 of the pairs of the second plurality of filaments can be multifilaments of about 200 dtex.

FIG. 5 shows a cut-out of the manufactured woven retention device 110. As can be seen from FIG. 5, the woven retention device can be manufactured using biaxial braiding.

In some embodiments, the interweaving of the first and second plurality of filaments can create a balanced state of the woven retention device. FIG. 6A shows an embodiment where the configuration of the weaves results in a balanced state from diameters of the first plurality of filaments equaling diameters of the second plurality of filaments. In one embodiment, each filament of the first plurality of filaments can be a same thickness and each filament of the second plurality of filaments can be a same thickness. In another embodiment, as depicted in FIG. 6A, the first plurality of filaments includes filaments of alternating thicknesses 604, 610 and the second plurality of filaments includes corresponding filaments of equally differing thicknesses 606, 612. In this manner, the woven retention device can be balanced. In one embodiment, the woven retention device 110 in the balanced state can resist torsion in clockwise and counterclockwise directions. The balanced state of the woven retention device 110 can allow for a more stable, rigid and durable structure such that the protuberances of the woven retention device 110 are substantially uniform in both direction of torsion pressure.

In other embodiments, the woven retention device 110 can be configured to be in an unbalanced state. In one embodiment, the unbalanced state can result from diameters of the first plurality of filaments not equaling diameters of the second plurality of filaments. For example, in FIG. 6B, each of the filaments of the first plurality of filaments is one thickness 614 while each of the filaments of the second plurality of filaments can have a different thickness 616. Being in an unbalanced state allows for torsion resistance in one direction but collapsing upon pressure being exerted in the opposite direction. For example, the woven retention device 110 in the unbalanced state can either open up with pressure being exerted in the one direction or it can collapse itself down on each other, which can be changed by changing which bobbins were loaded on so that they will actually open up, they would resist collapsing but they would open up and/or potentially get larger. This unbalanced state may offer a few advantages depending on the type of screw, the size of the screw, the type of thread that it is used and depending on the type of bone.

In some embodiments, the interweaving can form a textile strength of the woven retention device 110 that is changed based on pique count, filament thickness, braid angle, and bobbin count.

In some embodiments, the loading pattern can be configured with a carrier map, which associates each carrier with a corresponding filament.

In some embodiments, the method of manufacturing can include collapsing the hollow structure into a flattened tube and winding the flattened tube around a spool; and unwinding the spool and cutting the spool into individual segments. The woven retention device can be woven over a mandrel to fabricate the right structure and that whole structure can be collapsed down into a flattened tube and then wound around a spool. Then that spool can be taken and unwound and cut into individual segments. In one embodiment, all bobbins of a left side can come in together in an interweaving pattern over a mandrel. The right hand side of that mandrel is a take up reel, take up spool, and it spools up all of these filaments in the final structure. Once that spool is full, that spool is then removed and taken to another machine in which it will be heat set so that it retains its tubular structure. In one embodiment, heat setting affects the structure of the resultant manufactured woven retention device so that the structure retains the mandrel size. In some cases on the manufacturing basis, the mandrel may be heated so that it actually goes through the heating process simultaneously and then it is cut at the very end into the reciprocate lengths. In some embodiments, the method of manufacturing can proceed from one step to another and the spooling continuously produces woven interlaced material, which can be processed as needed for cutting. In this manner of spooling bulk material, efficiency of the process can be improved.

In one embodiment, the mandrel can be heated to shape the interwoven filaments. Once manufactured under one set of temperature constraints such that its resultant configuration or resultant form is one state. And that state is not altered either by temperature or by release of mechanical restraints. A mechanical force can be imparted thereby allowing, for example, to expand and interdigitate, but when that force is removed, the woven retention device can return to its normal state.

Another embodiment can be seen in FIG. 10 of triaxial braiding. In one embodiment, the interweaving can include interweaving the first and second sets of filaments with a set of longitudinal filaments, the interweaving creating a triaxial braid. In this embodiment, a biaxial braid can have longitudinal yarns 1010 inserted at each horn gear, fibers can be in both axial and bias direction, the sleeve can have a locked diameter or width, and the fiber orientation can range from 10-80 degrees.

Triaxial filaments can be arranged along a longitudinal axis of the mandrel or woven retention device, whereas the other fibers can spin about the core. So these longitudinal fibers are introduced in just that manner longitudinally off of a separate spool. And then the interlacement occurs around them with the fibers that are either rotating clockwise or counter clockwise. Thus, the interlacement around the core introduced adjacent to the core can include the longitudinal fibers in a third axis, and can comprise the triaxial braiding. There may be some axial strength associated with the triaxial braid.

In one embodiment, triaxial braiding can be used to make the woven retention device non-expandable. That is, in a filament braiding orientation with longitudinal fibers, depending on how these other fibers are orientated, one over one under, and how this is kind of woven through it, the longitudinal fibers can lock the woven retention device and prevent the other filaments from sliding relative to each other so it does not expand or get thinner. Embodiments using triaxial braiding can be applied to act as a splint, for example, as a pedicle liner or a lined pedicle, such that the woven retention device is minimized in its movement, expansion, and shrinking down. Thus, interweaving can include interweaving the first and second sets of filaments with a set of longitudinal filaments, the interweaving creating a triaxial braid.

In one embodiment, the method of manufacturing can include tapering a distal portion of the woven retention device 110. The woven retention device 110 can be braided in a way so that a closing on one end is achieved. The woven retention device 110 can be closed (tip can be made) via interweaving of the filaments.

In other embodiments, the tapered end can be created via energy (heat stake, laser, optical, ultrasound energy to melt fibers), and chemical (glue (superglue)). The end does not need to be completely closed, however, partially open is possible, but size of opening would have to accommodate pushing means. A hexagonal braiding technique can be employed, as shown in Schrieber pp. 1-4.

Although the foregoing description is directed to the preferred embodiments of the invention, it is noted that other variations and modifications will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the invention. Moreover, features described in connection with one embodiment of the invention may be used in conjunction with other embodiments, even if not explicitly stated above. 

What is claimed is:
 1. A method of manufacturing a woven retention device, the method comprising: providing a loading pattern of a first plurality of filaments on a first set of tensioned carriers and a second plurality of filaments on a second set of tensioned carriers; rotating the first set of tensioned carriers in a first direction and rotating the second set of tensioned carriers in a second direction; and interweaving the first and second plurality of filaments at a predetermined braid angle of intersection to form the woven retention device, the woven retention device having an inner diameter, wherein the interweaving creates pairs of the first plurality of filaments and pairs of the second plurality of filaments, wherein spacing in between the pairs results in a plurality of aperture sizes through the woven retention device, and wherein each of the filaments of the first plurality of filaments and the filaments of the second plurality of filaments have an offset weaving configuration.
 2. The method of claim 1, wherein the filaments of each of the pairs of the first plurality of filaments have an offset two-over/two-under weaving configuration and the filaments of each of the pairs of the second plurality of filaments have an offset two-over/two-under configuration.
 3. The method of claim 1, further comprising rotating a plurality of rotors including the first and second tensioned carriers, wherein a first set of the plurality of the rotors rotate in the first direction and a second set of the plurality of rotors rotate in the second direction.
 4. The method of claim 3, wherein each rotor has at least four inlets that are configured to accept carriers, the at least four inlets having a predetermined spatial relationship that includes the at least four inlets being unevenly spaced, wherein the rotating includes carriers alternatingly switching either from one of the at least four inlets of one of the first set of the plurality of rotors to one of the at least four inlets of one of the second set of the plurality of rotors or from one of the at least four inlets of one of the second set of the plurality of rotors to one of the at least four inlets of one of the first set of the plurality of rotors, wherein the carriers alternatingly switching in a predetermined spatial configuration creates the interweaving, and wherein the carriers alternatingly switching in the inlets having the predetermined spatial relationship around the rotors creating the offset two-over/two-under configuration.
 5. The method of claim 4, wherein the at least four inlets comprise a first and a second pair of inlets, and wherein for each rotor, the predetermined spatial relationship includes both inlets of each pair being about a same distance from each other.
 6. The method of claim 1, wherein the filaments are about 0.2 mm in diameter.
 7. The method of claim 1, wherein the filaments are about 0.1 mm in diameter.
 8. The method of claim 1, wherein the filaments are about 0.4 mm in diameter.
 9. The method of claim 1, wherein ones of the pairs of the first plurality of filaments are about 0.1 mm in diameter and others of the pairs of the first plurality of filaments are about 0.2 mm in diameter, and wherein ones of the pairs of the second plurality of filaments are about 0.1 mm in diameter and others of the pairs of the second plurality of filaments are about 0.2 mm in diameter.
 10. The method of claim 1, wherein ones of the pairs of the first plurality of filaments are about 0.1 mm in diameter and others of the pairs of the first plurality of filaments are about 0.4 mm in diameter, and wherein ones of the pairs of the second plurality of filaments are about 0.1 mm in diameter and others of the pairs of the second plurality of filaments are about 0.4 mm in diameter.
 11. The method of claim 1, wherein ones of the pairs of the first plurality of filaments are about 0.2 mm in diameter and others of the pairs of the first plurality of filaments are about 0.4 mm in diameter, and wherein ones of the pairs of the second plurality of filaments are about 0.2 mm in diameter and others of the pairs of the second plurality of filaments are about 0.4 mm in diameter.
 12. The method of claim 1, wherein ones of the pairs of the first plurality of filaments are about 0.1 mm in diameter and others of the pairs of the first plurality of filaments are about 200 dtex, and wherein ones of the pairs of the second plurality of filaments are about 0.1 mm in diameter and others of the pairs of the first plurality of filaments are about 200 dtex.
 13. The method of claim 1, wherein the interweaving of the first and second plurality of filaments creates a balanced state of the woven retention device, and wherein the woven retention device is configured to resist torsion in clockwise and counterclockwise directions.
 14. The method of claim 13, wherein the balanced state results from diameters of the first plurality of filaments equaling diameters of the second plurality of filaments.
 15. The method of claim 1, wherein the first set of tensioned carriers includes 24 carriers and the second set of tensioned carriers includes 24 carriers.
 16. The method of claim 1, wherein the first plurality of filaments includes flat multifilaments and the second plurality of filaments includes round monofilaments.
 17. The method of claim 1, wherein the interweaving forms a textile strength of the woven retention device that is changed based on pique count, filament thickness, braid angle, and bobbin count.
 18. The method of claim 1, wherein the braid angle of the filaments is between about 40 and 45 degrees.
 19. The method of claim 1, wherein the loading pattern is configured with a carrier map, which associates each carrier with its filament.
 20. The method of claim 1, further comprising providing a mandrel wherein the interweaving uses the mandrel to create the hollow structure shape.
 21. The method of claim 20, wherein the mandrel is heated to shape the interwoven filaments.
 22. The method of claim 1, further comprising: collapsing the hollow structure into a flattened tube and winding the flattened tube around a spool; and unwinding the spool and cutting the spool into individual segments.
 23. The method of claim 22, further comprising tapering a distal portion of the woven retention device.
 24. The method of claim 1, further comprising tapering a distal portion of the woven retention device.
 25. The method of claim 1, wherein the inner diameter is about 6.5 mm.
 26. The method of claim 1, wherein the interweaving includes interweaving the first and second sets of filaments to create a biaxial braid pattern.
 27. The method of claim 1, further comprising providing a plurality of longitudinal filaments, wherein the interweaving includes interweaving the first and second sets of filaments with a set of longitudinal filaments, the interweaving creating a triaxial braid.
 28. A system of manufacturing a woven retention device, the system comprising: a first plurality of filaments on a first set of tensioned carriers and a second plurality of filaments on a second set of tensioned carriers, the first set of tensioned carriers being configured to rotate in a first direction and the second set of tensioned carriers being configured to rotate in a second direction; and a mandrel that is configured to interweave the first and second plurality of filaments at a predetermined braid angle of intersection to form the woven retention device, the woven retention device having an inner diameter, wherein the interweaving creates pairs of the first plurality of filaments and pairs of the second plurality of filaments, wherein spacing in between the pairs results in a plurality of aperture sizes through the woven retention device, and wherein each of the filaments of the first plurality of filaments and the filaments of the second plurality of filaments have an offset weaving configuration. 